Dual-modality Tomography for Gas-Liquid-Solid Three Phase Flow Imaging: A Simulation Study

摘要

The electrical tomography techniques are suitable for monitoring the multi-phase flow behaviors, primarily due to its advantages of fast response, non-invasive and real-time imaging capability. The dual-modality tomography technique that combines the capability of two or more tomographic modalities can provide the complementary information for better understanding of investigated multi-phase flows. However, the dualmodality technique requires some effective fusion methods to make better use of the additional information that obtained from the different modalities. In this paper, the multi-class LS- SVM has been proposed for implementing the dual-modality fusion between the two tomography modalities, i.e., the electrical capacitance tomography and electromagnetic tomography. In consideration that the multi-phase flow is extreme complex in phase distribution, consequently, the studies are conducted by combining the computational fluid dynamic (CFD) and finite element method (FEM) simulation. The phase distributions that approximate to the real situation can be collected by performing CFD simulation. By feeding the distributions into the electromagnetic field simulation, one can obtained the interelectrode capacitances and mutual inductances between coils, i.e., the ECT and EMT measurements, by FEM simulation. Subsequently, the corresponding tomographic images and fusion images can be achieved. Furthermore, the phase volume fractions and distributions can be quantitatively evaluated to verify the feasibility of proposed method. Simulation results show that the fusion method can distinguish the measured three phases with sharp boundaries and obtain the three-phase distributions in several flow regimes.